Printing apparatus



April 16, 1963 Filed Dec. 5l, 1959 W. G. PAIGE ETAL PRINTING APPARATUS 6Sheets-Sheet 1 1N VEN TORS.

W. GR|FF\N PAIGE PAUL R. HOFFMAN April 16, 1963' w. G. PAlsE ETAL3,085,504

PRINTING APPARATUS lFiled Dec.i 31, 1959 6 Sheets-"Sheet 2 Fig. 2

lso |76 1N VEN TOR.

W. GRIFFIN PAIGE PAUL R. HOFFMAN AGENT )l BY April 16, 1963 w. G. PAIGEETAL PRINTING APPARATUS 6 Sheets-Sheet 3 Filed Dec. 3l, 1959 JNVENToRs.w. GRxFFlN PAIGE PAUL R. HOFFMAN 1MM, K. /ll

AGENT April 16, 1963 w. G. PAIGE Em. 3,085,504

PRINTING APPARATUS Filed Dec. 31, 1959 6 Sheets-Sheet 4 JNVENTORS. iq/5w. GRIFFlN PAlGE BY PAUL R. HOFFMAN AGENT April 16, 1963 w. G. PAIGEETAL 3,085,504

PRINTING APPARATUS Filed Dec. 31, 1959 6 Sheets-Sheet 5 AGENT April 16,1963 w. G.PA1GE ETAL PRINTING APPARATUS 6 Sheets-Sheet 6 Filed Dec. 5l,1959 vom INVENTORS.

W. GRIFFIN PAIGE PAUL. R. HOFFMAN o o BY QS AGENT 08m m www. o

3,085,564 PIIENTENG APPARATUS Waiter Griihn Paige, Paoli, and Paul E.Hoffman, Woodlyn, Fa., assignors to Burroughs Corporation, Detroit,Mich., a corporation of Michigan Filed Bec. 31, 1959, Ser. No. 863,3641l Claims. (Cl. itil-93) This invention relates to novel printingapparatus and particularly to high speed multiple printing apparatus.

More particularly, this invention relates to printers which print withpreformed type and utilize a platen over which a document is passed andthe print is impressed from the front. These printers have Severalfavorable features in that they produce a high quality impression, andthe printed `line becomes immediately visible. These machines print onany stock thickness that can be wrapped around a platen, and handle anywidth of continuous roll paper or single documents of random width.

The speed yof most platen front printing machines is limited by thelarge masses which carry the type members, by the necessity to stop orslow down the printing elements and return each to its home position,and by the time required to select one of the many characters containedon the element. The high speed of the printing machine of the presentinvention is due to the shape and mounting of multifaced printingelements and to time sharing in the movement of operating parts of theapparatus for the selection of characters. In front printers ofconventional construction each printing element has one character faceand can move vertically only in one direction. ln the apparatus of thepresent invention, each printing element can be reciprocated past theprinting line of the platen, and while this movement is occurring it canbe rotated about its axis to one of its character bearing faces.

The principal object of this invention -is to provide an improved highspeed printing apparatus for effecting multiple printing operations.

Another object of this invention is to provide an improved printingapparatus capable of effecting full line printing at high speeds andwith economy in the number and design of the operating parts.

Another object of this invention is to provide in printing apparatusnovel shaped printing elements and associated parts which enable theelements to be closely spaced in side by side arrangement relative to adocument which is to be printed upon and which further enable theseelements to be simultaneously displaced, lineally and rotatably, topresent a selected one of a multiplicity of characters on each elementfor printing.

Another object of the invention is to provide in printing apparatusimproved means for imparting both linear and rotatable displacementssimultaneously of the printing elements and for controlling theoperation thereof.

In carrying out the objects of the invention, a printing mechanismembodying the invention includes a plurality of type elements or barsarranged opposite a print-receiving document. Each type bar includes aplurality of type bearing faces and is mounted for rotation in a carrierwhich may be moved past the platen of the mechanism. The elevation ofthe type bar as well as the selection of a given face thereof isdetermined by signals from electrical control circuits. The selection ofone of the faces of each type bar is caused by the movement of a pinionwhich is twisted through an angle by a pair of racks which engageopposed surfaces of the pinion. With each cycle of machine operation thetwo racks reciprocate in opposite directions in a manner to cause theaxis of the pinion to remain stationary but imparting rotativeoscillation to the pinion. The pinion is connected by a torsion wire tothe type bar and. in the present embodiment of assetti Patented Apr. 16,1963 the invention an arresting member (having a like number of -facesas the print bar) is provided which follows the motion ofthe type bar.

A locating electromagnet infront `of each arresting member will, whenenergized, act thereupon to stop further rotary motion of the type barwhile at the same time its driving ytorsion wire absorbs any additionaltorque applied thereto by the racks. A pawl structure and actuatingmeans therefor, upon signal from the control circuits, will cause thepawl structure to engage the carrier and interrupt its lineal movementto thus present a selected character opposite the platen for printing.Thereafter the print hammer associated with each carrier is released todrive the print bar to the platen, where the character impression isproduced on a document overlying the platen.

Various other objects, advantages and meritorious features will becomemore fully apparent from the following specification, appended claimsand accompanying drawings, wherein:

FIG. 1 is a perspective view of a printing apparatus embodying theinvention;

FIG. 2 is a vertical sectional View through the apparatus of FIG. 1;

FIG. 3 is a sectional view similar to FIG. 2 but in larger scale showinga different position of the operating parts thereof;

FIG. 4 is a sectional view of the type bar actuating mechanism showingthe position of the parts for immobilizing a type bar of the apparatus;

FIG. 5 is a greatly enlarged view of one of the prismatic print bars andassociated elements connected thereto for controlling its operation;

FIG. 6 is a composite view showing the three faces of one of theprismatic type bars;

FIG. 7 is an enlarged cross sectional view taken along the line 7-7 ofFIG. 5;

FIG. 8 is an enlarged cross sectional view taken along the line 3-8 ofFIG. 5;

FIG. 9 is an enlarged cross sectional view of the arresting member takenalong the Aline 9--9 of FIG. 5;

FIG. l0 is an enlarged cross sectional View of drive pinion for a printbar taken along the line lll-10 of FIG. 5;

FIG. ll is an enlargedcross sectional view of the print bar taken alongthe line 1].-11 of FIG. 6';

FIG. 12 is an enlarged cross sectional view taken along line 12--12 ofFIG. 5 and illustrating the angular displaced relation of its type barto its arresting member;

FIG. 13 is an enlarged cross sectional view taken along the line 13-13of FIG. Z showing the members for arresting rotation of a type bar;

FIG. 14 is a greatly enlarged sectional view taken through line 14-14 ofFIG. 2 showing the relation of the hammer mechanism to the type carrierand type bar;

FIG. l5 is an enlarged elevational view partly in section, illustratingthe position of the type bar before striking the platen;

FIG. 16 is a view similar to FIG. 15 but showing the type bar instriking engagement with the platen;

FIG. 17 is an enlarged longitudinal sectional view through a portion ofthe platen illustrating different positions of a plural number of typebars with respect thereto;

FIG. 18 is an enlarged sectional view through a group of adjacent typebars showing their close proximity to one another and different rotativepositions assumed thereby;

FIG. 19 is a schematic View illustrating an electrical control circuitfor controlling the operation of the apparatus;

FIG. 19a is a view of a portion of a record member utilized forcontrolling the operation of the apparatus.

The various figures illustrate a preferred embodiment of the inventionof which FIG. 1 shows the general organization thereof. The printingmechanism includes certain supporting members which may comprise a baseplate 20, a left side plate 22 and a right side plate 24. Bridging thespace between the side plates are certain major operating elements ofthe mechanism including a platen 26 around which a print receivingmember or sheet 28 may be partially wound in the manner illustrated inFIG. 1. The opposite ends of the platen may be suitably journalled inthe side plates for intermittent rotation for advancing the sheet fromline position to line position in a conventional manner. The preferredembodiment of the invention is capable of printing a whole line ofcharacters on the sheet at one time and for this purpose a plurality ofmulti-faced rotatable type elements or bars 30 are provided, one at eachprinting station. The number of such printing elements may vary but forprinting wide sheets, as many as 120 elements or type bars may bemounted in close side by side relation in the mechanism. Also bridgingthe space between the side plates are two shafts 32 and 34, the formerserving to control the operation of print hammers 36, one of which isshown in FIG. 1, and the other serving to provide driving cams forcontrolling the vertical reciprocation of the type elements. As will bedescribed in more detail hereinafter, each type element or bar 30 isrotatably journalled in a carrier or frame 38 and the two together arecapable both of vertical reciprocating movement and lateral movementtoward and away from the platen. In addition, each type bar has anindependent rotative movement about its longitudinal axis relative toits carriers.

Externally of the side plate 22 there is shown in FIG. 1 certain drivingelements for operating the movable parts of the mechanism. An endlessdriving belt 40 which is connected to the source of power, not shown,such as an electric motor, drives sheave wheel 42, which, through pinion44, drives larger gear wheel 46 fixed on the extremity of the hammeroperating shaft 32. An endless belt 48 is driven from a sheave wheel 50on shaft 32 past the idler 52 to sheave wheel 54, carried by stub shaft56. The stub shaft is journalled in the side plate 22 and as will bedescribed in more detail hereinafter, carries a cam barrel 58 slotted asat 60 for driving a pair of reciprocating racks 62 and 64. The two racksextend across the space between the two side plates below and in linewith the type elements or bars 30 and serve as will be describedhereinafter to rotate these elements to present their different faces tothe platen. As will be described in more detail hereinafter, theconnection between the cam barrel S8 and the rack bars `62 and 64 issuch as to reciprocate these two shafts in time sequence, but inopposite directions to one another, to impart the desired rotarymovement to the type elements.

Included in the printing mechanism are certain control devices forselecting the desired character of each type element for printingimpression upon the record member or sheet 28. Such devices areelectrically operated and controlled from a circuit such as that shownin FIG. 19. In general the control devices are in a form ofelectro-magnetic instrumentalities. Three banks of such magnetic devicesare generally indicated at 66, 68, and 70 which, as shown in FIG. 1,extend across the space between the side plates 22 and 24 and aresupported thereby. 1

Magnetic devices 66 are used to control the vertical movement of thetype carriers 38 during the time that the toothed rack members `62 and64 impart rotational movement to the type bars 30 through a 240 degreeangle and return in a manner which will be described in detailhereinafter. When the face of each type bar carrying the selectedcharacter which is to be printed is rotated so that it is opposite theplaten, the magnetic devices 68 lock and prevent the type bar fromrotating further. The final vertical position of the type bar is fixedwhen magnetic devices 70 thereafter activate pawl structure to engageand arrest the type carrier against further vertical movement. Thisoccurs when the selected character is thus positioned at its properelevation opposite the platen. Thereafter rotation of the print hammercam shaft 34 to its drop off position permits the print hammers to bepowered by drive springs to strike the back of the type carrier and tothus impact the type bars against the platen.

It may be briefly mentioned at this time that each type bar 30 ismounted for rotation in its carrier 38 and it will be understood that asimilar mounting is provided for the remaining type bars in the printerat each character position along the platen. Because of the novelprovision for applying rotative movement to all of the type bars from adriving device common to all, and other economies in the operatingparts, the size of the printer may be made considerably smaller thanline printers heretofore developed. The illustrated embodiment of theinvention may be roughly about 12 high and 12 deep, and its width ofcourse will be dependent on the number of print bars employed in theprinter.

The print or type bars "30, of which there can be any number, are spacedin the present embodiment on 1/10 centers, lO to the inch. As seen nowin FIGS. 2, 5 and 6, each type bar 30 exhibits the form of a narrowequilateral triangular prism which may have upper and lower sets ofprinting characters formed on the three faces thereof. The three facesof each type bar assume an equilateral triangle and in order to provideextremely close side by side spacing of the type bars, the apexes ofthese faces may be suitably bevelled as shown in the cross sectionalviews of FIGS. 7, ll and 18. As best seen in FIGS. 3 and 6, the type bar30 normally stands in a neutral position such that its mid-pointdesignated by the reference character 31 lies opposite the printing lineposition of the platen 26. Each type bar is rotatably mounted in thetype carrier or frame 38 for rotation about its longitudinal axis andfor this purpose includes integral spindle extensions of reduced crosssection designated 72 and 74, and an intermediate reduced portion 76which are mounted in bearing portions 78, 8l) and 82 respectively of thetype carrier.

Depending from the lower extremity of each type bar is an elongatedtorsion member 84 of reduced cross section which serves to transmittorque to the type bar 30. A suitable construction for the torsionmember is a narrow cylindrical rod or wire of beryllium copper alloy.Secured to the lower end of torsion wire 84 is an elon gated generallycylindrical member 86 which serves to transmit torque from thepreviously mentioned rack members 62 and 64 to the type bar 30 which isxed in a similar manner to the upper end of the torsion wire. 'Iheelongated cylindrical member 86 is formed with toothed portions orsplines 88, such as shown in FIG. l0, which extend lengthwise along theouter periphery of the member are for a distance substantially greaterthan the height of the rack members which drive the same.

'In order to arrest the rotation imparted to the type bar 30 by thetoothed member 86, an arresting sleeve member 90 is shown encircling theintermediate portion of torsion wire 84 and may be xed thereto in anysuitable manner, such as by having its upper end tightly crimped orsoldered to the wire as shown at 92 in FIG. 5. As shown in FIG. 9, thebalance of the arresting member is hollowed interiorly to provide a bore94 which is slightly larger in diameter than the wire 84 and permits thetorsion stresses or twists to occur over a major portion of the wire.The member which is arrested is moreover shown in the present embodimentof thc invention as be ing of the same general external conguration asthe type bar and has three at faces, 96, 98 and 10i) which form t anequilateral triangle in cross section as shown in FIG.

9. The faces of the arresting prism 90 are preferably angularly offset45 with respect to the printing faces of the type bar 30 and this may beseen in greater detail in FIG. l2. Thus, the apex formed by the faces 96and 100 is aligned with the center of the printing face 30a of the typebar, while the apex formed by the faces 96 and 9S is similarly alignedwith face Sile of the type bar and the remaining apex is thuscorrespondingly aligned with the remaining face Stirb thereof. Thelength of torsion wire 84 between the secured upper end 92 of thearresting member 90 and its securement to the lower end of the type barprovides a flexible driving connection which not only transmits torquebut is sufficiently flexible to allow the lateral movement oi' thecarrier 3S and its type bar toward and away from the platen for printingimpact upon the recording member or sheet 23.

As earlier mentioned herein, sleeve 9i) forms part of the mechanism forarresting rotation of the type bar 30 with which it is associated.Mounted adjacent to the side of each sleeve opposite to the carrier 3d,there is provided a detent device controlled for movement into and outof engagement with the sleeve 9h and when so engaged acting to hold thesame and the type bar from rotation. A preferred detent device comprisesa grooved vwheel 102 shown in FIGS. 3 and 13. The groove of the wheelcorresponds to the angularity of the side faces of the sleeve 9d asshown in `FlG. 13 such that when the wheel is moved `into engagementtherewith the walls of the groove make surface contact with two adjacentsides ot' the sleeve thus securely holding the sleeve and the type barfrom rotative movement. The wheel 132 is freely journalled on a pin 10dmounted across the upper biurcated end of a lever 106. As shown in PEG.3, the opposite lower end of the lever is pivoted lon a pin 03 securedto the upper edge of a cross bar lid which serves similarly to supportthe pivot pins and levers of the remaining detent devices of themachine. The lever we is yieldingly urged out of engagement with itsrespective sleeve 9i? by means of a spring 112 tixed at one end, such asto the lower end of the cross bar Zilli?, and secured at the other endto a small projecting arm M4 forming a lateral extension of the lever inthe manner shown in PEG. 3. Under control of signals from the controlcircuit, the lever 1% is forced toward the sleeve 9i? against theresistance of spring M2 to bring its wheel MZ into locking engagementwith the sleeve. For this purpose, there is provided a push rod 116 kforeach lever which, as shown in ilG. 3, is in abutting engagement with theside of the lever opposite the sleeve. The push rod is actuated by oneof the electromagnets 11S in the bank of magnetic devices 68. The pushrod is coupled to the armature 12% of the electr-omagnet by a suitablecollar ft2?. rlxed to the push rod. The opposite end of the armature1219 may be hinged to a wall member of the bank itl in any suitablemanner, and it is apparent upon energization of the magnet H8 it willattract the armature and push the rod 116 in the direction of the leverand cause interlocking engagement of the wheel le?. with the sleeve 9d.When this occurs the selected apex of the arresting sleeve 9) enters thegroove of the wheel, and the wheel thus restrains the sleeve and itsassociated type bar from further rotation, and moreover correctly alignsthe selected face ot the type bar so that it is in printing position.The wheel 120, because of its journal mounting on pin ldd, however,permits longitudinal travel tof the arresting sleeve 3) even though itis in locking engagement therewith. This enables the sleeve andassociated torsion wire and printing bar to be vertically positionedwhile it is held from rotation.

With reference to FiGS. l, 2 and 3, each carrier 38 and its type bar .3dmounted therein is guided for vertical reciprocation so that the twosets of type characters on each of the three faces of the prismatic typebar may be presented opposite to the printing platen 2'6. When themachine is at rest, the type bar 30 is in its neutral position so thatone set of printing characters on each face lies above the printing lineof the platen and the other set of characters on the same face lie belowthe printing line. The lower portion of each type carrier 38 is slidablyreceived in a slot of a comb member 13th extending across the machinewhich prevents sidewise movement of the carrier, but at the same timeoperates to guide the carrier for vertical movement. In a similar mannerthe comb 13d serves to guide the remaining type carriers of the machine.

Each type carrier 38, in addition, includes two sets of teeth 132 and134, along its lower edge portion, the spacing of each toothcorresponding to the vertical distance or displacement between adjacentcharacters of each set of characters on the faces of the prismatic typebar. Thus, corresponding to each character on the type bar as seen inFiG. 6, there is a corresponding tooth on the type carrier. On each ofthe three type faces, as seen in FIG. 6, there are shown nine charactersabove the midpoint 3i and nine characters or symbols below the midpoint,-and in the same manner, the set of teeth 132 includes nine teeth andthe set of teeth 134 likewise includes nine demarcations. The two setsof teeth 132 and E34 are preferably longitudinally spaced apart on thecarrier and oppositely inclined to one another as shown in IFlGS. 2 and3. As will be brought out in greater detail later, the medium whichcontrols the operation of the printer determines in which direction thetype bar shall travel, that is, up or down.

F or providing the reciprocating movement of each type bar and carrierassembly, there are provided two actuators in the form of levers and i4@mounted in superposed relation to one another and in straddling relationto the cross shaft 34 previously mentioned. With reference to FIGS. 2and 3, it is to be noted that the 'two levers are outwardly bentintermediate their respective length to also straddle a cross framemember i142 which has its ends supported in the side plates 22 and 24 ofthe machine. The ends of the levers adjacent to the type carrier y38 aretapered to provide relatively pointed extremities, each of which isreceivable in a notch located on the rear side of the type carrier. Thepointed end 144 of the upper lever is receivable in notch 146 of thecarrier; and the pointed end 148 of the lower level 144 is receivable inthe notch 150 of the carrier. The opposite or rear ends of the leversare pivotally connected to the arms of a bell crank lever 152 which yis.pivoted at its midportion to a frame member 154 extending across themachine from one side wall to the other. The rear end of the upper leveris connected by pin 156 to the upper arm of the bell crank lever andsimilarly the rear end of the lower lever is connected by pin 15S to thelower arm of the bell crank lever. In FlG. 2, the two levers are shownin full line in the normal or at rest position of the machine. The twolevers, however, are capable of movement outwardly away from one anotherfrom their full line positions shown in FlG. 2 to the dotted linepositions illustrated in that figure. It is to be noted that in thenormal or at rest position of the levers that the pointed end M8 of thelower lever is in engagement with its respective notch 150 whereas thepointed end 146 of the upper lever is free or clear of its respectivenotch "1416. it is apparent that if in this position a slightlycounterclockwise movement is imparted to the bell crank lever 152 itwill project the pointed end of the lever 138- into its notch in thecarrier while at the same time withdrawing the pointed end of the lowerlever 1li-0 from its respective notch in the carrier.

For the printing of each line of characters, the two levers 138 and 146are urged outwardly away from one another and if one or the other isengaged with its respective notch in the carrier it will cause thecarrier to partake of this same movement. To provide the opening andreturn movements of the two levers, there are provided a pair oftransversely extending hails 160* and 162, the former bail being locatedabove the upper lever 138 in approximate alignment with the shaft 34 andthe latter bail being located below the lower lever 140 likewise inapproximate alignment with the shaft and the other bail. Each bail maybe similarly formed out of a narrow strip of metal and extends acrossmachine and has its opposite ends mounted for swingable movement aboutan axis toward and away from the shaft 34. As shown in FIG. 2, the loweredge of the upper bail 160 is inturned upon itself in the form of aU-shape to serve as an abutment 164 for engaging the upper tier oflevers `1318. The opposite edge of the upper bail is outwardly turned toform a ange 166. A spring 168 is connected to each upper lever 138 atone end and to the tlange 166 of the bail at the other end. The lowerbail 162 is similarly formed as the upper bail having an abutment 170for engagement by the lower tier of levers 140 and a flange 172 betweenwhich and each lower lever a spring 174 extends. Each spring 168 or 174yieldingly urges its respective lever against the abutment of its bailand tends to cause the lever to follow the movement of the bail.

Each bail, as previously mentioned, is swingable about an axis towardand away from the shaft 34. For this purpose the opposite end of theupper bail is secured to arms or segments 176 located externally of thetwo side plates, one associated with each side plate. The lower bail 162is similarly secured to arms 178 externally of the side walls. Toprovide clearance for the movement of the bails between their innermostand outermost positions, the side walls of the machine are provided withcutouts. For the upper bail 160, each side plate is provided with anoutwardly opening cutout 180 extending slightly short of the shaft 34.For the lower bail 162 each side wall is provided with similarly shapedaligned opening 182, suicient clearance being provided by the opening toallow swinging movement of the bail about its axis.

During the operation of the machine the two bails 160 and 162 are causedto be simultaneously moved away from the shaft and returned during eachline printing cycle. This is accomplished in the illustrated embodimentof the invention by the provision of rollers, and a cam carried on eachextremity of the rotating shaft 34. One cam is shown at 184 which, asshown in FIG. 1, is mounted on the shaft 34 externally of the left sideplate 22 partially under the larger gear wheel 46. The shape of the camis illustrated by the dotted outline thereof appearing in FIGS. 2, 3 andby a full line thereof in FIG. 4. A similar cam is mounted on theopposite extremity of the shaft 34 externally of the right side plate24. As probably best shown in FIG. 4, each cam is double lobed, that is,it is provided with t-wo rises approximately 180 degrees apart from oneanother. Riding on each cam are a pair of rollers for guiding the bails.The roller for the upper bail is indicated at 1186 and is journalled toa pin axed to the outer side of the ann 176. The roller for the lowerbail 162 is indicated at 188 and is similarly mounted with respect toarm 178. It is evident that upon continuous rotation of the two cams 184in the same direction that the rollers will r-ide thereon and causetheir respective bails to oscillate about their respective pivotalmountings on the side plates. As this movement occurs the two levers 138and 140 will be urged by their respective springs 16S and 174 to followthe bails. The return movement of the levers is preferably cushioned bymeans of a resilient strip 190 secured to the cross member 142 andextending the length thereof. Each lever opposite the cushioning stripmay be provided with a lateral flange forming a heel for abutmentagainst the strip as shown in FIGS. 2, 3 and 4. To guide the levers intheir movements, the cross member 142 may be provided along its upperand lower edges with combs, indicated at 192 and 194 respectively, inthe slots of which the levers are disposed for guidance in theirmovement.

Normally, as earlier mentioned, the pointed end of the lower actuator orlever 140 is received in its respective notch of its associated typecarrier and upon move ment of the bails outwardly away from one anotherit will be urged by the spring 174 to follow the lower bail and in sodoing move the carrier 38 and its respective type bar downwardly tocause the upper groups of characters on the faces of the type bar totraverse the printing line position. If, on the other hand, the bellcrank lever 152 is oscillated slightly counterclockwise it will move thepointed end of the upper actuator or lever 133 into engagement with itsrespective notch 146 in the type carrier, which simultaneously withdrawsthe lower lever from its notch. The movement of the upper lever infollowing its bail will cause the carrier and its type bar to moveupwardly thereby causing the lower sets of characters on the type bar topass by the printing line position.

Rocking movement of the bell crank lever 152 is ptovided by a push rod196 which, as shown in FIGS. 2 and 3, abuts a at 198 provided on thebell crank lever. The movement of the push rod 196 is controlled by anelectromagnet 200 carried by the bank of magnetic devices 66. Thearmature 202 of the electromagnct is coupled to the push rod and uponenergization of the electromagnet it will urge the rod outwardly thusrocking the bell crank lever counterclockwise to produce the shift inposition of the two levers 138 and 140. Associated with each bell cranklever is a spring 204 connected at one end thereto and at the oppositeend to any fixed portion of the machine such as a flange projecting fromthe housing for the bank of magnetic devices 66, this spring yieldinglyresisting the counterclockwise movement of the bell crank lever andreturning the same to the initial starting position followingde-energization of the electromagnet 200. The head 206 on the push rodmay serve as a spacer which upon abutment with the adjacent wall of thebank 66 limits further clockwise movement of the bell crank lever andresets the two levers in the normal starting position thereof shown inFIG. 2.

It is evident, therefore, from the description thus far, that no signalis required to energize an electromagnet to cause the lower lever 144 tomove the type carrier and type bar downwardly and in the absence of asignal this would occur during each line printing cycle. However, if theelectromagnet 200 is energized by an electrical pulse applied thereto,as will be later described, it will shift the positions of the twolevers 138 and 140 and cause the former to engage the type carrier andmove the same upwardly in timed sequence with the outward movement ofthe upper bail 160. It is to be noted that the two levers 138 and 140are not required to following the movement of their respective bails butare yieldingly urged to do so by the springs 16S and 174.

When the type carrier 38 is moved vertically, one or the other of thesets of teeth 132 or 134 corresponding respectively to the characters onthe upper and lower half portions of the type bar are moved past aposition arresting device including a rockable shoe 210 having teethengaging portions at each end thereof. When a particular selectedcharacter is opposite the platen, the shoe is urged into engagement withthe associated tooth corresponding to that character. For this purpose,the shoe 210 is articulated as at pivot 212, the latter being carried bythe upper end of a bell crank 214 which in turn is pivoted at its lowerextremity as at 216 on a transverse frame member 218. A spring 220engaging an upper arm portion of the bell crank 214 at one of its endsand secured to a hook portion 222 affixed to the transverse frame member218 at its other end yieldingly urges the bell crank in a clockwisedirection. In its normal position the shoe 210 is free of the toothededges of the type carrier 38 and thus permits movement of the two setsof teeth past the shoe member. Upon receipt of a code signal anelectromagnet 224 of the bank of magnets 70 will become energized andattract its armature 226 which in turn will impart movement to push rod228 to urge the bell crank 214 in a counterclockwise direction againstthe tension of the spring 220. Depending upon which direction thecarrier 38 is in motion past the arresting shoe 210, the upper or lowerouter edge portions of the shoe may engage either set of inclined teeth132 or 134 along the type carrier. When so engaged, the shoe holds thecarrier and its type bar from further vertical movement. This in turnrestrains further swinging movement of the actuator lever 138 or 140,`as the case may be, from following its respective bail. The bailsprings 168 and 174 stretch under these circumstances as the bailscontinue to swing to their outermost positions. Disposed above the upperedges of the shoes and bell cranks 214 is a transverse -frame member 230which includes comb-like slots 232 which restrain the bell cranksagainst lateral or sidewise movement during their pivotal travel. Theengagement of the shoe with a tooth of either set of teeth disposedalong the edge of the carrier completes the character selection for itsassociated type bar.

Thereafter, in the printnig cycle as previously mentioned the type bar30 and carrier 3S may be moved forwardly toward the platen to make theprinting impression on the document. The forward movement of the carrieris provided by a slight fulcruming action thereof about the upperterminal end of the base of the slot of the comb member 13D in which itis guided. It will be recalled that at this time in the printing cyclethe turn arresting lever 166 pivoted thereto has been moved to bring thewheel into locking engagement with the sleeve 90. To provide theimpacting motion of the type bars, the previously mentioned hammers 36are slidably guided in slots of comb members 236 and 238 which extendtransversely between the inner surfaces of the side plates 22 and 24.The forward end portion of each hammer is reduced in height to provide ahead for abutting the rear side of the associated carrier at the sarneelevation as the printing line position on the platen, The rearwardportion of each hammer 36 is generally arcuately shaped as indicated at243 so as to partially surround the hammer cam drive shaft 32 andincludes a right angle heel shaped insert 244 of high wearing qualitylocated on the inner edge of the extremity of the arcuate portion of thehammer.

The hammer drive shaft 32 includes a pair of drop-off cut-outs located180 apart and extending substantially the length of the shaft. The heelportion 244 of each hammer is urged into the cut-outs when the latterare brought into alignment therewith. Each hammer is powered for forwardmovement by a spring 246 which is connected at one of its ends to thecrest of the arcuate portion 243 of the hammer land at its opposite endto a post 24S projecting upwardly from the comb member 236. Thus whenone of the drop-off notches of the hammer shaft 32 is opposite the heelportion of the hammer 36 the spring 246 urges the hammer forward anamount equal to the depth of the notch and in doing so it abuts andmoves the type carrier 38 and its associated print bar 3) toward theplaten thus to make a printing impression upon the document 2S. It isunderstood that for visible recording a suitable inked ribbon or thelike is interposed between the hammers and the document. It is observedthat the lateral portion of the heel 244 of each hammer rides on theupper surface of a transverse guide member 250 bridging the spacebetween the side plates 22 and 24 and supported thereby. Furtherrotation of the hammer shaft 34 will cause the camming surface thereofto retract the hammer 36, and at the same time thereby stretch the powersprings 246, so that the hammers are restored to their neutral positionas shown in FIG. 2, prior to the start of a further printing cycle.

For resetting the hammers, each hammer 36 is provided with a forwardhooked extension 240 which, as best shown in FIG. 14, overlies the rearside portion of its associated type carrier 38 and is received in anelongated vertical recess 242 of the carrier. The extension moves withIthe hammer and is ineffective when the harnmer drives the carrierforwardly to make a printing impression. However, when the hammer isreturned to its starting position, the hooked end of the extensionengages the rear wall of the recess 242 and retracts the carrier to itsnormal position. At times during the cycling of the machine one or moreof the type carriers and their respective type bars may not bevertically moved. To avoid impact of such unmoved type bars with thedocument, the rear edges of the carriers 3S, as shown in FIG. 18, areeach provided with a notch 245. In the neutral position of the carriers,these notches are in line with the path of travel of the heads of thehammers and the heads enter these notches without abutting the carriersand thus avoiding applying an impact force thereto.

With reference now to FlGS. 2 and 4, provision is made for disablingeach type bar and its carrier at its column position along the printingline. This enables the operator to vrender ineective cert-ain of thetype bar operating mechanisms to obtain .a desired format of printedmaterial on the document or to immobilize a useless group of type barsif the document is shorter in width than the row of type bars in themachine. For this purpose each upper actuator lever 138 is provided withan inclined surface 256 :at `its rearmost extremity. Associated witheach such lever is a manually Ioperable arm 25S pivotally mounted on apin 266 within a slot of a transverse comb member 262 aixed in anysuitable manner to the machine such as the wall of the housing for thebank of magnetic devices 264. The arm 25S includes an enlarged or lobeportion 266 serving as a cam which when the yarm is rotated in theclockwise direction to full line position shown in FIG. 4 eng-ages thepreviously mentioned surface 256 to thrust the upper lever i138 in theforward direction. When so rota-ted against the action of spring 264 thetoe portion 144 of the upper lever 138` will move into its mating notch146 of type carrier 38, but not sufciently to fully withdraw the toeportion 148 of the lower lever 140 from its mating notch 150. With bothlevers so engaged in their associated type carrier, as shown in FIG. 4,the outward movement of the upper and lower bails 16)t and 162 willmerely stretch their associated springs .168i and 174 without impartingany motion to the type carrier 38. 1t is evident in this condition thatthe two bails exert through their respective associated levers 13S and14S equal and opposite forces on the associated type carrier 33 and thusno total movement accrues to the type car- =rier. To releasably holdeach arm 253 in disabling or nondisabling position, a spring detent 261-is provided which is yieldingly received in spaced notches on thepivoted end of the arm in the manner illustrated in FIGS. 2 and 4.

The marmer of absorbing the impact forces occurring during Contact ofthe printin-g type bar 30 with the platen 26 `and paper 2S is best shownin FlGS. 15 and 16. With reference rst to FIG. 15, it is observed thatthe two bearing portions 78 and S2 of each type carrier 38 are slightlyelongated in the direction of its printing impact movement, showngreatly enlarged for clarity. The lower bearing portion 30, not shown inFIG. 15, is similarly elongated. The spindle extensions 72 and 74 ofeach type bar 30, as well as the intermediate spindle portion 76thereof, are thus provided with a slight play in the carrier yin thefore `and aft direction of movement thereof. Normally the resultingslight clearance, shown at 73 for the top spindle 72, will be at theright of the spindles of the type bar as illustrated in FIG. 15. Thetype bar and carrier assemblies yare so designed that when a selectedface of `a type bar is in impact printing position, a clearancesubstantially equal to that for the type bar spindles is providedbetween the apex 77 of the type opposite to the selected face and :theforward edge of the type carrier 38. This clearance is indicated at 79in FIG. 15 and extends the length of the type bar. When, however, thetype carrier and associated type bar have been moved forwardly to strikethe platen, the apex 77 is brought into line contact with the leadingedge of the carrier 38 and correspondingly the clearances for the typebar spindles designated by reference characters 73 and 75 in FIG. 15have correspondingly been absorbed and now appear to the left of thespindles as shown in FIG. 16. By means of this provision the sheerstresses which would occur at the spindle portions are eliminated andthe impact force is transmitted from the leading edge of the carrier tothe confronting apex 79l of the type bar along the length thereof.

To provide the torque to rotate the type bars 30 in their respectivecarriers 38, a common means for all the type bars is provided. In theillustrated embodiment of the invention such means comprises the twopreviously mentioned rack bars 62 yand 64 which, as shown in FIG. 1, aresquare shaped in cross-section for the major portion of their lengthswithin the machine. For supporting and slidably guiding these -supportbars for reciprocal motion each bar is provided with a cylindricalextension at each end thereof extending through suitable bushings in theadjacent side plate of the machine. One such extension for the rack bar62 is indicated at 270 in FIG. 1, and that for the rack bar 64 at 272.The inner faces of thc rack bars, as illustrated in FIG. `l, areprovided with teeth which mesh with the elongated pinions 86 carried onthe lower ends of the torsion bars 84. To reciprocate the rack bars inunison, but in opposite directions to one another, an operatingconnection is provided between the cam barrel 58 and the cylindricalextensions 270 and 272 located adjacent thereto. The illustratedconnection comprises a rocking arm 274 pivoted adjacent one end onbracket 276 on an axis indicated at 277 located between the twoextensions of the rack bars. The other end of the rocking arm isprovided with a cam follower 278 which rides in the groove 60 of the cambarrel 58. The shape of the groove 60 is `so designed that during one1'0- tation of the cam barrel it rocks the arm 274 first in onedirection and then in the other and thereby imparts a reciprocatingmotion to the rack bars 62 and 64 causing them in 'turn to move in onedirection opposite to one another and then return in the oppositedirection. The reciprocating movement of the rack bars applies torque tothe type bar pinions 86 while keeping their axes stationary, and in turnthis torque is transmitted by the torsion wires 84 to the type bars.Although the pinions 86 are lifted or lowered concurrently with the typebars, nevertheless due to their elongated extent the pinions maintainmeshing engagement with the teeth of the rack bars regardless of theposition they :assume with respect thereto.

The three-faced or prismatic construction of the type bars 30,especially when their apexes are beveled or charnfered in the mannerpreviously described, enables them to be assembled or packed in veryclose proximity to one another as shown by the group of type bars inFIGS. 17 and 18. Regardless of whether selected ones of the type barsare locked against rotary motion or not, they are sufficiently clear ofone another to rotate on their axes relative to one another. As shown inFIG. 18, two of the Itype bars, the third and fifth of the group, havebeen restrained from further rotary movement to present one of theirfaces for printing while the remaining 4three type bars are shown asundergoing equal angular displacement beyond the held type bars. Duringeach machine cycle the type bars of the present embodiment of theinvention are oscillated about their respective axes 240 to successivelybring their respective faces opposite to the platen. By virtue of thecommon drive means for applying torque to all of the type bars, theywill, unless restrained by the locking devices, oscillate the sameangular distance and in the same direction in unison about theirrespective axes and thus by this provision avoid the necessity ofproviding individual means for applying a separate torque to each typebar. FIG. 17 exemplifies the action of a group of the type bars 30 withrespect to the platen 26 and a document 28 thereon. Several of the typebars 12 are shown in this figure at the instant of impact with thedocument to print two words while the remaining type bars are shown ashaving been rendered inelective so as to provide the spaces between thewords.

As illustrated in FIGS. 1 and 2, the banks of electromagnetic devices66, 68 and 70 are shown as mounting their respective devices in groupsof four, each group occupying a common vertical plane. This compactarrangement is desired because of the larger dimensions of these devicesas compared with the width of the type bars and their associatedoperating elements. In the arrangement shown, each such group of fourelectromagnets have their respective operating connections made to fourad jacent type bar operating assemblies in the machine. Thus, it is tobe understood that the push rods 116, 196 and 228, similar to thosealready described, are connected to and actuated by the armatures of thethree remaining electromagnets in each grouping thereof in the banks. Asshown in the drawings the push rods may be of varying lengths to reachthe armature to which they are connected.

Although electrical signals may be derived from any suitable source forenergizing the electromagnetic actuators in the banks 66, 68 and 70, onedesirable method of input data decoding is shown on FIG. 19. The inputdata are assumed to be obtained from a record member, such as a card280, FIG. 19a, similar to cards used by some tabulating businessmachines. The card contains the coded information for printing a line ofcharacters in one cycle of machine operation. This card enters and isretained in a card sensing chamber 281 provided with brushes 282 whichprovide circuit continuity through punched holes 283 in said card. Theillustrated card 280 has the coded holes therein provided in crossingrows and columns, the rows extending vertically in FIG. 19a and thecolumns extending horizontally. As indicated by the brackets in thefigure, the card is divided into two zones, the first zone containingrows designated R, X and O and the second zone containing rowsdesignated 1 to 9 inclusive. Each column on the card is representativeof a particular columnar printing position produced by the machine, theorder of the card columns corresponding to the order of the type barsfrom one to the other end of the platen. The information in the firstzone of the card determines the direction of vertical movement of thetype bars, whether up or down, and also determines the selection of oneof the three faces of the type bars to be presented to the platen forprinting.- The information in the second zone of the card determines thepositions at which type bars will be arrested in their verticalmovements.

For the purpose of this description it is assumed that the presence ofan R hole in each column of the card selects one side or face of thetype bar 30 corresponding to the card column, the presence of an X holeanother side of the type bar, and the absence of either R or X hole thethird side of the type bar. The presence of an O hole in a card columncauses the corresponding type carrier 38 to rise, the absence of an Ohole causes the carrier to depress. The presence of a 1 to "9 hole agiven card column will cause the arrest of the vertical motion of thecorresponding type carrier 38 at the elevation corresponding to thenumber of the hole. It is understood that the coding on the recordmember and the arrangement of the letter characters on the type bars maybe varied.

The circuit shown in FIG. 19 is representative of a control circuit forone type bar operating assembly, it being assumed that a similar circuitis provided for each of the remaining type bar operating assemblies. Thesensing of holes in the card rows R, X and O will energize correspondingstorage relays 284, 285 and 286. Relays 284 and 285 continue beingenergized through the provision of current limiting resistors 287. Thethird relay 286 need merely be pulsed to momentarily close its circuitthrough switch 302 which is suicient to shift the upper lever 133 towardthe carrier and bring its toe portion into engagement with itsrespective notch 146 where 4the toe portion will be retained through theupward movement ot' the carrier by sliding eng-agement of its heel platealong the side of the cross frame member 142. The three relays 284, 285and 286 establish a circuit continuity from the input line 364 to theturn arrest electromagnet 118 and the direction control electromagnet200i. Switches 291, 292, 293 and their respective operating cams 288,239, 290, which are driven synchronously by the bail drive shaft 34,cause through turn arrest actuator 118 the type bar to be arrested atthe position pre- 1etermined by the energization of the relays 284, 235and 286 and to release actuator 118 at the same point of the returnstroke of the rack bars 6'2 and 64, thus avoiding unnecessaryoscillation of the arresting sleeve 99 and subsequent overstressing ofthe torsion wire 84. Switches 28S, 2%9 and 2% determine when and howlong the turn arrest -actuator 118 is energized.

Circuit breaker 294, which may be operated from shaft 341, causes allrelays to drop out at the proper cycle point. The elevation stopactuator 224 becomes energized through one of the l to 9 holes of thecard by the provision of a rotating brush commutator 2% which may befixed to shaft 34 for moving in synchronism with the type carrier 38.When brush 2% senses a hole in the card it closes circuit to relay 30denergizing the same and closing switches 36S and 210v and providing aclosed circuit from input line 3M through switch 311i to stopelectromagnet actuator 224. Thus, when rendered conductive, brush 295will select one of the nine teeth contained in either set of teeth 132or 134 in the type carrier 38 in either the up or down stroke thereof,whichever direction has been determined by the presence or absence of aO hole in the card.

As an example of the printing operation, if it is desired to print anampersand & by one of the type bars, one of the columns of the card 280in FIG. 19a so designated in the left margin is provided with punchedholes in each of the 0, X and 7 row positions thereof. The presence ofthe O hole causes energizing of relay 286 and results in the movement ofupper lever 138, which requires only a momentary actuation ofelectromagnet 2% as previously described. The presence of the i holeenergizes relay 235 and closes switches 297 and 301. Relay 236establishes circuit continuity through Contact 362 from the input line3114 to elevation actuator 299 thus causing the selection of antip-stroke for the type carrier. At the same time circuit continuity ismade from the input line through switch 292, now closed by cam 2S9 andclosed relay Contact 301, to tum-arrest actuator 113 at 153 of themachine cycle. Upon energization, actuator 118 positions the type bar sothat the side thereof containing the & is facing toward the platen. Asshown in FIG. 6, the ampersand 8a is spaced seven character positionsfrom the neutral or mid-point of the type bar. Simultaneously the risingof the type carrier continues and when the brush 295 senses hole 7 ofthe card the electromagnet actuator 224 stops further movement of thetype carrier and associated type bar. After completion of the printcycle, the rotation of cam 289 will bring its drop-off surface oppositeto switch contact 292 opening the same. This will release the turnarresting actuator 118 at the same point of the return stroke of therack bars 62 and 64.

As another example, when coded information is indicated on the card 2S@for a number, such as 5, to be printed, there will be an absence ofpunched holes at the R, X and O positions in the column of the cardcorresponding to the selected type bar. The absence of an O causes thetype carrier to be depressed. Since none of the relays 284, 285 and 286become energized, the circuit is closed to the turn arrest actuator 11Sby the closing of switch 295 by cam 22d during the rotation of thelatter from 216 to 280 thus placing the side 14 face of the type barcontaining number characters opposite to the platen, and the type bar isarrested at the fth tooth during its down stroke when commutator brush295 senses the number 5 hole on the card. The printing cycle will becompleted in the manner described in the previous example.

Having described a preferred form of the invention it will be understoodthat other forms thereof will fall within the scope of its teaching andthe following claims:

What is claimed is:

1. In printing apparatus, an elongated type carrier, an elongatedmulti-faced type bar journalled for rotation about its longitudinal axisin said type carrier, each face of said bar having two longitudinallyspaced apart groups of printing characters thereon, one group of suchcharacters disposed normally above and the other group of suchcharacters disposed normally below a printing line position of theapparatus, means for linearly moving the carrier and the type bartogether in opposite directions to cause either the upper or the lowergroups of characters to pass the printing position, a pawl structure andmeans for causing the structure to engage the carrier during its linealmovement to interrupt said movement, torsion wire means connected to thetype bar, means for applying torque to rotate the torsion wire means andthe type bar during said lineal movement, and means for arrestingrotation of the type bar while torque is applied to the torsion wiremeans, whereby a given type character contained in a given group ofcharacters on a given face of the type bar may be presented forprinting.

2. In a printing device, a type carrier, an elongated multi-faced typebar journalled for rotation on said t-ype carrier, each face of said barhaving two spaced apart groups of type characters thereon, one groupdisposed normally above and the other below a vertical printing lineposition of the printing device, means for selectively moving thecarrier lineally to cause either group of characters to pass theprinting position, a pawl structure and means for causing the structureto engage the carrier during its lineal movement to interrupt saidmovement, torsion Wire means connected to said type bar, elongatedpinion means connected t0 said torsion wire means, a pair of slidablemembers each having a series of rack teeth, said members being arrangedto move in parallel paths, said pinion means mutually coacting with theteeth of each of said members, means connected to said members to causethe same to move in opposite directions and to impart rotative movementto sai-d pinion means and said type bar through said torsion wire meansWithout displacement of said pinion means in a direction normal to itsaxis, a sleeve member having a like number of faces as said type ybarencircling said torsion wire and secured to said type bar, wheel means,and means for causing the twheel means to move into engagement with apair of adjacent faces of said sleeve member to stop the rotation of thesame whereby said torsion wire permits said pinion to complete itsrotation while the sleeve member is locked against rotation while at thesame time permitting lineal movement of the type lbar and pinion underthe action of the lineal moving means associated with the type carrier.

3. In a printing device having a platen, a type carrier, an elongatedtype bar exhibiting the shape of a triangular prism having typecharacters on its three faces thereof, said faces being disposed to forman equilateral triangle,

f means for selectively moving the carrier lineally to cause thecharacters to pass a printing position, means for engaging the carrierduring its lineal movement to interrupt said movement, means forrotating said type fbar to present one of said faces to said platen,said type bar being journalled on said carrier for rotation about itsaxis such that when one of said faces is disposed in its printingposition relative to said platen the apex of the type bar opposite tosaid face is juxtaposed along an edge of the carrier, said type barbeing journalled in said carrier with sufficient clearance to permitrelative movement 15 therebetween and toward one another to enable saidapex to engage said edge of said carrier in line contact therewith, andmeans for impelling the type bar and carrier toward the platen wherebythe impact stresses of the type bar with the platen are absorbed anddistributed in line contact of said apex with said edge of said typecarrier.

4. In printing apparatus, a type carrier, a multi-faced type barjournalled for rotation in said carrier about its longitudinal axis,means for moving the type bar along said axis, yieldable means aixed tosaid bar and aligned with said longitudinal axis, means connected tosaid yieldable means for applying torque thereto to effect rotation ofsaid type bar and to present its faces sequentially to a printingposition, and means for arresting the rotation of said type bar whilethereafter increasing the torque applied to said yieldable means so thata selected one of its faces is stopped in a printing position wherebysaid yieldable means is twisted about said longitudinal axis.

5. In printing apparatus, a type carrier, an elongated multi-faced typebar journalled for rotation about its longitudinal axis in said carrier,means for moving said type bar along said axis, torsion means affixed tosaid bar, means for applying torque oscillatibly to said torsion meansto effect rotation of said type bar in opposite directions about itslongitudinal axis to present its faces sequentially to a printingposition, and means for arresting the rotation of said type bar so thatone of its faces is stopped with a selected type in said printingposition while the further torque applied by said torque applying meansto said torsion means is absorbed in deformation of the latter.

6. In printing apparatus, a multi-faced type bar journalled for rotationabout its longitudinal axis, torsion means secured to one end of saidtype fbar, pinion means secured to said torsion means, rack meanscoacting with said pinion means for applying torque to said torsionmeans to turn said type bar about its longitudinal axis, and means forarresting the rotation of said type bar while said rack meanscontinuously applies torque to rotate the pinion means which operates totwist said torsion means.

7. In printing apparatus, a multi-faced type bar journalled for rotationabout its longitudinal axis, a torsion rod connected at one end to saidtype bar, a pinion secured to the opposite end of the torsion rod, meansfor rotating said pinion means to effect turning movement of said type-bar about its longitudinal axis so as to present its faces sequentiallyto a printing position, and means for selectively arresting the turningmovement of said type bar to dispose one of its faces in the printingposition while said rotating means through said pinion continues toapply torque to the torsion rod, said torsion rod acting to absorb bytwisting on its axis the continued application of the torque after thetype bar has been arrested.

8. In printing apparatus, a plurality of multi-faced type [barsindividually journalled for rotation about their respective longitudinalaxes, means for oscillatibly rotating the type bars about theirrespective axes including a torsion element individual to each type -barand serving to transmit driving torque thereto, the oscillatiblyrotating movement applied to each type bar sequentially presenting itstype faces to a printing position in the apparatus, rotation limitingmeans in one position thereof individual to each type bar forselectively arresting its rotation while torque is concurrently appliedto the torsion element to rotate the latter, each torsion elementtwisting on its axis to absorb the torque applied thereto after therotation of its respective type bar has been arrested, said rotationlimiting means being movable to a second position out of engagement withthe type bar whereby said torsion element is restored to its untwistedposition, and means for moving said rotation limiting means between saidone and second positions.

9. In printing apparatus, a like plurality of elongated multi-faced typebars each journalled for rotation about and for bodily movement alongits axis, a pinion associated with each type bar, a torsion elementconnecting each type bar with its associated pinion, rack means commonto said pinions and operable to apply torque thereto to rotate thetorsion elements and the type bars in unison, means for bodily movingsaid type bars along their respective longitudinal axes and carryingtheir respective pinions along therewith while the same are beingrotated by said rack means, and means for selectively arresting therotation of the type bars to present one of their respective faces in aprinting position while torque is continuously applied by the rack meansto rotate .the pinions, said torsion elements thereby twisting on theirrespective axes to absorb the applied torque after the rotation of theirrespective type bars have been arrested.

l0. In printing apparatus, an elongated print member having portions ofits longitudinal extent shaped in the iform of a three-faced prism, typecharacters carried on each of the three faces of one of the prismportions of the member, means journalling the opposite ends of the printmember for rotation about its longitudinal axis,

means for rotating the print member on its axis to present the differentfaces thereof for printing, and a per-ipherally grooved wheel engageablewith any one of the apexes of another prism portion of the print memberand acting when so engaged to releasably hold the member from rotation.

`ll. In a printing apparatus, a plurality of type carriers, a pluralityof elongated type bars each in the form of a equiangular triangularprism and corresponding in number to said carriers, a plurality of typecharacters disposed upon each of the lateral faces of said prism, saidtype bars being closely spaced one to another and each, journalled forrotation about its longitudinal axis in a corresponding carrier, a pairof rack means common to al1 said type bars, means for actuating eachrack means in an opposite direction with respect to the other to therebyrotate said type bars about their longitudinal axes, whereby the lateraledges of each type bar formed by intersections of its lateral facesthereof are in approximate touching contact with lateral edges of typebars on each side of and immediately next adjacent thereto.

References Cited in the le of this patent UNITED STATES PATENTS 543,164Weiss Iuly 23, 1895 723,567 White Mar. 24, 1903 1,333,890 Wright Mar.16, 1920 1,542,223 Dolph June 16, 1925 1,926,891 Bryce Sept. 12, 19332,157,035 Torkelson May 2, 1939 2,320,810 Carroll Iune l, 419432,577,092 Sampson Dec. 4, 1951 2,709,959 Beattie June 7, 1955 2,847,105Carroll Aug. 12, 1958

4. IN PRINTING APPARATUS, A TYPE CARRIER, A MULTI-FACED TYPE BARJOURNALLED FOR ROTATION IN SAID CARRIER ABOUT ITS LONGITUDINAL AXIS,MEANS FOR MOVING THE TYPE BAR ALONG SAID AXIS, YIELDABLE MEANS AFFIXEDTO SAID BAR AND ALIGNED WITH SAID LONGITUDINAL AXIS, MEANS CONNECTED TOSAID YIELDABLE MEANS FOR APPLYING TORQUE THERETO TO EFFECT ROTATION OFSAID TYPE BAR AND TO PRESENT ITS FACES SEQUENTIALLY TO A PRINTINGPOSITION, AND MEANS FOR ARRESTING THE ROTATION OF SAID TYPE BAR WHILETHEREAFTER INCREASING THE TORQUE APPLIED TO SAID YIELDABLE MEANS SO THATA SELECTED ONE OF ITS FACES IS STOPPED IN A PRINTING POSITION WHEREBYSAID YIELDABLE MEANS IS TWISTED ABOUT SAID LONGITUDINAL AXIS.